Process for the production of sound records with a metallic base for talking machines



July 16, 1935. w. BIBER 2,008,092

PROCESS FOR THE PRODUCTION OF SOUND RECORDS WITH A METALLIC BASE FOR TALKING MACHINES Filed April. 19. 1

@TToe/VEY tti) iPatented July 16, 1935- tratti PROCESS FOR THE PRODUCTION 0F SOUND RECORDS WITH A METALLIC EASE FR TALKING MACHINES wilhelm Biber, Metallophon Glarus, Switzerland Berlin, Germany, assigner to Company,

Aktiengeeciiscliait,

Application April 19, 1932, Serial No. 606,299 In Germany April 11, 1931 3 Claims.

My invention relates to the production of sound records'with a metallic base. Records produced according to my invention are free of noisy sounds, the record will not be altered by the use and can not be iniiuenced by the temperature or Weather or other atmospheric conditions. Such records are unbreakable and flexible without destroying the sound grooves. To obtain a slight weight, light metal as aluminium or aluminium alloy is used and the blank-is coated with lacquer as cellulose lacquer, oil lac or the like.

The process is characterized by the fact, that the metallic material of the record is prepared before the sound groove mass is applied thereto, so that the adhesion of the sound groove mass isassured.

' In accordance with this invention, the surface of the record is coated with a preferably extremely thin nlm made of a material, which i sticks securely to the metal on the one hand and on the vother hand is capable of taking or absorbing the sound groove mass well, so that a united coating of the metal disc can be obtained, which remains secure, does not exhibit any cracks and the like, and besides possessing great durability, has the property of softness necessary for obtaining a good tone having no objectionable accompanying effect. l

To serve as the intermediate lm, a solution of varnish with turpentine oil is-applied to form a very thin film, for example by spraying, and

for the purpose of speeding the production, is quickly dried in an oven. There can also be used with the intermediate lm, fine gum-lacs which have the property of sticking tothe metal and to the sound groove coating. `Such thin lms can be applied repeatedly by coating the first film after drying with a second thin film ci. the same or other material; after the drying the sound groove mass will be applied. Such an intermediate nlm can be smoothed by sand paper and water, and then the layer with sound grooves is applied.

The sound groove mass, for instance a cellulose ester can be applied in the form of a layer on the prepared disc, preferably by the aid of heating or the mass can be applied by spraying,

painting or the'like in a finely divided form.

The sound groove mass is, for example mixed with extremely iinemetal dust, ior instance aluminium dust and bronze dust can be used. The

, amount of the metal dust to be added should not exceed about 6 to 8% of the disc mass.

Preferably nitrocellulose should not be used alone, but be mixed with a resin-like substance the melting point of which lies in the vicinityoi to 170 C. Artiiicial resins and natural resins or mixtures of them can be utilized together with a softener, for example blown castor oil or varnish or the like.

instead of lacquers or the like,`metals such as chromium can also be utilized for the aspirateiy The intermediate ilm can be also produced in such a manner that the metallic surface is coated with a thin layer of chromium and a thin coating of varnish or turpentine oil is applied on top of this layer. After the drying the sound groove carrying layer is then applied by spraying, dipping or the like. instead of cellulose esters and oil lacquers, resin lacs, Spiritus lacs, bitumen lacquers, asphalt lacquers or the like can be utilized.

After the record is dried, and warmed in the ress, the sound grooves can be impressed.

It is also possible to dry up the record till it has a certain plasticity and to apply the sound grooves without warming directly. For such a' process a suitable sound groove mass is necessary. n For the plasticity of the sound groove mass camphor or a camphor surrogate can be utilized, prei--v erably with cellulose ester.

The solvent, as for instance alcohol can be mixed with organical or anorganical salts to inuence the stability and the sound of the sound groove mass.

The invention will appear more clearly :from the following detailed description When taken in connection with the accompanying drawing showing, by Way of example only, a sound record in cross-section on a large scale.

In the drawing, the masses used for the production of 'sound grooves are designated by the letter a. The masses a surround an inner meil@ tallic layer c. Extremely thin layers b which adhere to the metallic layer'c and to the masses c are interposed between the metallic layer c and the masses a. is has been already mentioned, the sound groove masses a consist of a cellulose ester, while the layers b may consist oi a lacquer or a metal such as chrome.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, i'

declare that what li claim is:l

1. The process oi producing sound records comprising the application of a plurality oi thin by a bottom layer is formed, then superimposing upon said bottom layer without the use of heat further coats of said cellulose ester, partially drying said further coats, whereby a second layer constituting the sound groove mass is formed, and then forming sound grooves in said secondmentioned layer.

2. A process of producing` sound records comprising the application of a plurality ot thin coats of a. cellulose ester upon a metallic base then drying said coats to harden same, smoothing and polishing said coats whereby ai bottom layer is formed, then superimposing upon saldi bottom layer without the use of heat, further coats of said cellulose ester, partially drying said further coats whereby a second layer constituting the cellulose ester, partially drying said further v,coats whereby a second layer constituting the sound groove mass is formed and then forming sound grooves in said second-mentioned layer.

WILHELM BIBER. 

